


Side of the Angels

by lights_of_lisbon



Category: Sherlock (TV), Supernatural
Genre: Crossover, WIP
Language: English
Status: Completed
Published: 2014-02-22
Updated: 2014-02-27
Packaged: 2018-01-13 08:45:20
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,931
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1219924
Author URL: https://archiveofourown.org/users/lights_of_lisbon/pseuds/lights_of_lisbon
Summary: <blockquote class="userstuff">
              <p>Dean, Sam and Cas travel to London to investigate a series of hellhound murders that could possibly lead them to Crowley, and enlist the help of the world's only consulting detective and his loyal blogger. They'll have to learn to work together to stop the killings and capture the King of Hell himself. Implied Destiel and later Demon!John, may get a bit violent eventually.</p>
            </blockquote>





	1. Chapter 1

The case had started out so normally. Well, as normal as any of the cases that Sherlock deemed interesting enough to investigate were. A man head been found mauled to death by what looked like a large animal… in the middle of London. A few days later, a similar incident occurred when a famous journalist was found with her throat ripped out while jogging in a park, and a week after that a successful businessman was found torn to pieces in his penthouse. A quick inquiry revealed that no escaped animals had been reported missing from the zoo or any "private collections." A thorough investigation turned up nothing except a distinct lack of substantial leads and an increasingly frustrated, petulant, and irritating consulting detective, along with an army doctor who was seriously weighing the jail sentence that accompanied strangling one's flatmate against the continued tortured screeching of the violin that Sherlock swore helped him think.

"John," Sherlock's baritone pulled John, momentarily, from his murderous contemplations.

"Hmm?" John responded vaguely, glancing over the top of his open laptop at the backlit figure that stood staring sagely out of the window, violin lowered and bow hanging loosely from relaxed fingers.

"There are three men about to knock on our door." At his words, there came a brisk rapping from downstairs and the sound of Mrs. Hudson's shuffling footsteps and cheery greeting. The clatter of feet ascending the stairs drifted in from the hallway and, a moment later, three figures filled the doorway of 221B. Before the newcomers could even utter a word, Sherlock's rapid-fire deductions filled the air like a hail of bullets, "American, recently arrived but you didn't arrive here by plane, which begs the question: how did you get here? You obviously came to see us, well specifically me, but not for a consultation, no. Come to offer your meager skills on one of my cases, probably my current one, which is odd because this particular case, while admittedly strange and perplexing, is not controversial enough to warrant international attention. So the question remains: why are you here?"

After a moment of stunned silence, the tallest one broke the tension with, "Is he always like that?"

"Yes," John and the trench-coated stranger answered simultaneously. John gave the taller man an incredulous look, eyes widened in surprise, which the other returned with a squint and head tilt as if attempting to read John's mind.

"How did you – "

"Not important," the one with the striking green gaze interrupted John's amazed question. "All you need to know is that I'm Dean Winchester, this is my brother Sam, and our friend, Cas, and –"

"Friend!" Sherlock scoffed in disbelief before being silenced by one of John's infamous admonishing looks.

"Anyway," Dean continued after an awkward pause that was filled with the uncomfortable shuffling of feet and a knowing smirk from his brother, "we came to help you with your little hellhound problem."

"Hellhound?" Sherlock repeated with a note of scorn evident in his usually posh voice. "Preposterous. I've dealt with a case like this before and I can tell you that this isn't some creature made of fire and brimstone; it's a trick, a ruse, an elaborate front being used to conceal a common criminal with an undoubtedly mundane motivation. Dull."

"I can assure you that this beast is all too real and that it is the cause of these mysterious murders," Cas replied to Sherlock's scathing retort with a look so full of earnestness that it was hard not to believe him.

"This is ridiculous!" John finally exclaimed, rising from his armchair with an air of exasperation, running his fingers through his sandy hair and turning imploring brown eyes on his friend. "There's no evidence to support your theory and –"

"Ok then," Dean interrupted John for the second time, his frustration and lack of patience evident in his deep voice, "let's go over the evidence then: three people found ripped to pieces by a large animal in the middle of London. There are no witnesses, no fur or DNA found at the scene, and all were reported to have been acting strange in the days before their deaths. Now you tell me, what part of that sounds like a normal case?"

John continued to look doubtful, while Sherlock kept his countenance carefully schooled in an expression of cool removal, when Sam finally spoke, voice soothing, stepping in front of his brother with a glance that mirrored John's from earlier when he had silently berated Sherlock, "Look, we're not trying to argue, we just want to help."

"Even if we were to believe you, and I'm not saying that we do," John replied, "why would you come all the way from America for a… hellhound, or whatever the hell this thing is?"

"It's not the hellhound we're after, it's the guy who sent it," Sam responded, hazel eyes darkening at the change in the conversation. "A man named Crowley."

"Not a man; a demon," Cas picked up Sam's thread of explanation and elaborated.

"A demon," John echoed with more than a hint of disbelief apparent in his voice.

"Well, more like their King. The King of Hell, to be specific." Cas continued matter-of-factly, blue eyes analyzing the two Brits and gauging their reactions.

"Yeah, you know, demons," Dean expounded sarcastically, "Human souls that have been warped and twisted beyond recognition by the unimaginable and surprisingly creative torture dreamed up by those SOBs downstairs," Dean drawled casually, as if he were discussing the stereotypical London weather instead of corrupted souls.

"So demons, hmm?" Sherlock, who had been silent throughout the exchange, responded in a startlingly calm voice. "This requires more elaboration. Mrs. Hudson!" he shouted suddenly, "Do bring up some refreshments for our guests!"

"Not your housekeeper!" came the distant reply.

"Gentlemen, please take a seat and make yourselves comfortable," Sherlock continued with a semi-pleasant expression and a gesture at the various seats scattered throughout the sitting room, "we have much to discuss. Tea?"


	2. Chapter 2

**Summary for the Chapter:**

> Sherlock and John receive some unexpected help; in related news: Castiel is a BAMF.

Several hours and two pots of tea later, the newcomers had finished their story and sat clustered on the couch, John across from them, brow furrowed as he tried to take in the Americans' impossible story. Meanwhile, Sherlock sat curled up in his chair, hands in his signature prayer position and eyes closed contemplatively.

John finally broke the silence with a single phrase, "You honestly expect us to believe this load of rubbish?" Sherlock remained silent as John continued to rant at the Americans, "So you're telling us that you have to track down the King of Hell to retrieve the other half of some rock that apparently has Godly instructions on how to close the gates of Hell, that somehow these murders are connected to him, and that you need _our_ help to find him? Are you out of your bloody minds?" John finished, finally running out of breath and allowing the others to respond.

"That's about it in a nutshell," Sam answered John's incredulous question with a small shrug and pleading hazel eyes that would put a puppy to shame.

"Look," Dean spoke up, "I know it sounds crazy, and we probably wouldn't believe it ourselves if we hadn't experienced it first-hand, but you —" he was cut off by the shrill ring of Sherlock's cellphone. The exchange died into silence as Sherlock answered, "What is it, Lestrade?" A few moments passed wherein they could hear the Detective Inspector's voice distantly through the mobile, and Sherlock's answering words, when they came, were an abrupt disturbance whose tone held all the authority of one who was used to getting what he wanted, "Where? Fine, we'll meet you there. Make sure Anderson doesn't interfere, I don't fancy losing any of my brain cells."

As he hung up the phone, Sherlock strode to the door, grabbing his coat and tying his scarf around his neck in one fluid motion, "Well that was a lovely chat but it seems as if the Yard, incompetent as they are, have a lead on the real killer. I'm sure you can show yourselves out, come along John!" Sherlock finished in one breath, simultaneously dismissing the visitors and summoning his faithful shadow. They exited without a second glance, Sherlock shutting the door on three shocked faces.

* * *

 _I really need to get in shape_ John thought to himself as he puffed after Sherlock's receding footsteps. Although he had run through the Afghanistan desert in the middle of the hottest, driest season while wearing full combat gear, for some reason he found it difficult to keep up with Sherlock, whose long legs ate up the sidewalk and left John to trail behind.

"Hurry up, John! He's getting away!" Cursing under his breath, John put on a burst of speed and turned a corner only to crash into a very stationary consulting detective.

"What the hell —" John managed to get out before he was shushed by Sherlock.

"Quiet, the suspect is just ahead," Sherlock murmured as John made a grab for his friend in an attempt to keep from falling off balance.

"Shouldn't we wait for Lestrade?" John responded, a bit peevishly if he was honest with himself, while trying to quiet his post-sprint breathing.

Sherlock gave a condescending snort, "We'd be waiting here all night. I'm sure that the two of us will be able to sufficiently subdue him; he's scared, cornered, and unarmed. Simple enough." John had his doubts about their ability to successfully apprehend a dangerous criminal who was accused of killing at least three people. However, he kept his thoughts to himself as he didn't want Sherlock to try to capture the suspect by himself and risk getting injured (or worse).

At Sherlock's signal, the two moved forward in unison to stand at the mouth of the alley, "Come out with your hands up!" Sherlock intoned as John strained his eyes to peer into the inky blackness while keeping his gun levelled in the general direction of where he suspected the man to be hiding. "You're outnumbered and unarmed, if you surrender now it will be much less difficult for you," the detective threatened in an attempt to lure out their prey.

Shuffling footsteps came from the depths of the night-darkened shadows, and moments later a figure stepped into the flickering glow of an overhead streetlight. "Well, hello there, Mr. Holmes," the man greeted them with a slow smile and an expression of smugness that implied _he_ had them trapped instead of the other way around. As the pair drew warily closer, John's eyes skipped over the suspect as he began to catalogue any and all details that were readily evident, a habit left over from his military days where the ability to pinpoint possible danger could save your life. The man was taller than John, but not quite as tall as Sherlock, with mousy brown hair and wearing a cheap suit that possibly bespoke of an office job; overall normal and unremarkable. John hoped that Sherlock was getting more out of his own deductions than he, as the former soldier was concentrated on keeping the both of them safe and more or less unharmed.

"And look, it's your loyal dog," the man continued, turning empty, predatory eyes on the shorter man. John held his ground as the suspect's gaze casually took him in before flicking back to Sherlock with an air of obvious dismissal.

Sherlock ignored the man's attempts to goad them, simply stepping forward to apprehend the suspect, but paused at the man's soft words, "I didn't do it; I didn't kill those people."

"Yet all evidence points to the contrary," Sherlock responded, levelling an inscrutable gaze at the other man.

"Come now, Mr. Holmes. Does it really look as if I have three-inch fangs hidden behind this pretty smile?" the man was practically purring at this point.

Sherlock disregarded the man's remark and instead leapt straight to the point, "Then what were you doing at the crime scenes? And if it wasn't you, then who?"

The man sucked in a deep breath and assumed an injured expression, "Why, Mr. Holmes, you wound me. I was simply overseeing a business transaction; a final payment, if you will."

"And does your business usually result in brutal maulings?" Sherlock questioned, attention captured and body language like that of a bloodhound on a scent.

"On a good day," the man responded flippantly.

"Sherlock," John warned, speaking for the first time "don't let him pull you in."

"Oh look, you've taught your pet to speak. I guess it's wrong what they about old dogs and new tricks," the suspect sneered.

Suddenly, he was shoved up against a wall, the rough, weathered brick catching on the back of his suit jacket, "You still haven't answered my question," the detective practically snarled, finally losing patience with the suspect's semantics, "If you didn't kill those people, _then who did?"_

"I never would have pegged you for a man with a short fuse," the suspect remained infuriatingly calm for someone with an angry consulting detective in his face and gun pointed at his head. "Hellhounds, Mr. Holmes. They're quite cost-efficient, although they do tend to make a bit of a mess." He let out a manic laugh, as if amused by the look of shock and confusion on Sherlock's face. "You should have left it alone," he continued, irises disappearing as his eyes became pools of black, filled with dark intent and seeming to contain the very essence from whence nightmares were born.

Then, several things happened at once. The man threw off Sherlock, tossing him into the opposite wall as effortlessly as if he were nothing more than a ragdoll. John's gun rang out in three successive shots, smoke spiraling from the muzzle into the frigid night air, all three bullets hitting the man squarely in the chest, yet he continued to approach the army doctor unimpeded. The whoosh of wings cut through the frozen air and, suddenly, the trench-coated American — _No, Cas,_ John remembered distantly —appeared between the blogger and the suspect. John had a split moment for his brain to dart between _He's going to get himself killed_ and _How the hell did he just appear like that?_ before Cas stepped up to the man, gripping his throat and pinning him against the wall, feet dangling inches above the pavement. "Where's Crowley?" Cas growled without preamble.

"Nice try," the suspect scoffed, "but I'm not stupid. I'm more afraid of what Crowley will do to me than anything you feathered pansies could think of."

"In that case, you're very stupid," Cas rejoined, placing his palm over the suspect's face as a blinding flash of light exploded from the man's eyes and mouth, "You should be more afraid of me," he finished, addressing the slumped body at his feet.

Cas turned to the doctor, calm blue eyes meeting the panicked gazes of the two stunned Brits. "Maybe now you'd be willing to help us?"


	3. Chapter 3

**Summary for the Chapter:**

> Sherlock and John make a startling discovery about their new clients.

John had seen many incredible things during his career as an army doctor; but nothing that he had experienced in Afghanistan could come close, in terms of unbelievability, to the dream-like scene that had unfolded before him only moments prior. John stood, slack-jawed, staring at the man who had just killed that, that – thing, with a single touch and now stood staring at the two Brits passively, gaze inscrutable as ever and appearing no more disheveled than his usual rumpled, homeless tax accountant self.

John heard Sherlock pick himself up off of the pavement, wheezing as he did so from having the wind knocked out of him. Even as the doctor part of his brain worried over the possibility of his friend sustaining injuries from being flung into a brick wall, his overriding need for an explanation for the events of the past few moments eclipsed everything else as a few choice words exploded from his mouth, seemingly bypassing his brain completely to end with an emphatic, "What the hell was that?"

"That was divine retribution." Cas responded unblinkingly.

"But-but you just—and his eyes, they were black and then you just –" John broke off, pantomiming the light that had recently exploded from their suspect's orifices before ending with, "I shot him and he just kept coming like a bloody zombie or something!"

"Normal bullets don't work on them; you would have needed a weapon such as the Colt or a Kurdish demon-slaying knife to kill it." Cas replied, still as calm as if he were taking a midnight stroll through London instead of standing over the smoking body of a former murder suspect.

"I-I'm sorry, did you just say demon?" John reiterated, a smile of disbelief playing at the corners of his mouth, as if he expected the other man to burst into laughter and say _Gotcha!_ However, Cas remained impassive, tilting his head a bit and speaking slowly as if John were daft, "Yes, I did."

Sherlock finally decided to join the conversation, moving slowly and holding his side, "What just happened?" As the words left his mouth, the trio heard distant police sirens; it seemed as if Lestrade had finally managed to track down the detective and his (now very dead) suspect.

Instead of answering Sherlock's slightly breathless question, Cas sighed and suggested, "Maybe we should continue this conversation somewhere we won't be interrupted." As he spoke, Cas stepped forward, touching each man on the forehead with soft, dry fingertips before either could move away. John closed his eyes as the strangest feeling overcame him; a combination of displacement and faint motion sickness that made his stomach feel as if it was competing for the gold in tumbling in the 2012 London Olympics, but which was over after a single disconcerting moment. John was momentarily discombobulated when he blinked open his eyes and greeted with the warm, familiar interior of 221B instead of the damp and dank walls of the narrow alley that he had been expecting.

The Winchester brothers stood by the fireplace looking at the newcomers with startled expressions; Dean's gaze darted to Cas and they appeared as if they were trying to communicate silently. However, John spent no time attempting to decipher the two men's loaded looks as he moved closer to Sherlock, who had begun to sway dangerously.

"Hey! Hey it's ok, I've got you." John soothed as he led Sherlock over to his chair and began to unbutton the Belstaff in order to get at Sherlock's side, which he had been clutching ever since the alley and which John strongly suspected were cracked, if not broken completely.

"Stop fidgeting and let me see," John admonished as the injured consulting detective feebly swatted at John's prying hands, resisting the doctor's ministrations as per usual and softly protesting. John, however, was having none of it, and threatened Sherlock with a call to Mycroft if he didn't stop being difficult and let the doctor examine him. Sherlock descended into a sulky silence and finally allowed John to peel away his dress shirt to see the impressive black and blue splotch that now adorned his normally pale skin, like a mistake that someone had tried to erase but couldn't quite get the job done.

John was pulled from his mental diagnosis when he felt a presence behind him, spinning around to come face-to-face with the startlingly blue eyes of the man who had apparently transported them halfway across London in the blink of an eye.

"What's wrong with him?" Dean inquired pensively from somewhere behind an unnaturally still Cas. Not knowing what else to say, John answered the question in the voice of the trained medical professional he was, clearing his throat before laying out his hasty diagnosis, "From a cursory examination I can ascertain that he has bruised — possibly fractured — ribs, although it's difficult to say for sure without an X-ray."

As he addressed the brothers, John felt Cas' eyes pinned to him unwaveringly and when he glanced back, the other man was standing over Sherlock and reaching for his injury without John having any recollection of Cas moving past him.

"Oi!" John exclaimed in surprise and not a little bit of angry trepidation at the thought of him possibly injuring Sherlock further. But Cas laid his palm flat against Sherlock's side, and a moment later his friend let out a sigh of relief. When John pulled aside Sherlock's shirt, his ribs were miraculously healed, with no sign of the angry mottled bruise from only moments prior and appeared just as smooth and milky pale as usual.

John scrubbed a hand over his face, not even surprised in light of the events of what was quickly becoming the strangest evening of his life. "I reiterate," his muffled words came from behind hands that were still pressed into his face in an attempt to ground himself, "what in the bloody hell just happened?"

"I healed him," Cas' gravelly voice came from somewhere to John's right.

"How?" John asked wearily, bracing himself for whatever cockamamie explanation was to come.

Instead of answering directly, Cas replied, "I was introduced to you earlier as Cas; and while I am often addressed as such, my real name is Castiel and I am an Angel of the Lord."

"Castiel? As in Castiel, the Angel of Thursday?" Sherlock's baritone came from the chair behind John, who glanced over at him in surprise, unaware that he was even conscious or knew anything about something as seemingly frivolous as angels.

Sherlock answered John's unasked question with a simple explanation, "My mother was a pious Catholic and quite fervent in her veneration of saints and especially angels; as a consequence, Mycroft and I were required to memorize the names of every angel in the mythology."

"Violet Sherrinford-Holmes," Cas chimed in, drawing the confused looks of the other men in the room, with Sherlock appearing (understandably) astonished at the mention of his mother's name. Cas continued with a small, fond smile, "She was a kind, devout woman. She endured your father's infidelity with the grace that distinguishes a woman of faith." Shocked silence filled the room at Cas' startling revelation, with the angel still appearing blissfully unaware of the bombshell that he had just dropped into 221B. Sherlock, when John managed to sneak a surreptitious glance at him, remained stoic and expressionless at Cas' words, with only a small stain of pink coloring his regal cheekbones.

Sam cleared his throat, an awkward but effective break in the tense atmosphere that had descended on the flat like a storm cloud. "So, angels, huh?" John continued the previous conversation, allowing Sherlock to regain his composure, "Don't suppose you have any proof?"

"Proof?" Sam exclaimed in disbelief, "Do you really need to ask that after Cas just instantly healed your friend and revealed… things he wouldn't know otherwise?" he finished awkwardly, but apparently satisfied that he had gotten his point across.

"He's right, John," Sherlock joined in the conversation, appearing to have gotten over whatever discomfort Cas had briefly caused, "There is no other apparent explanation that can readily explain what we experienced tonight. Unless further evidence proves them wrong, we must proceed with the assumption that everything these men have said up until now is true."

John felt like it said a lot about what his life was like at the moment if the unfailingly logical Sherlock Holmes declaring that he believed in angels and the supernatural in general was the least strange thing that had happened all day. "Fine then," he continued with a what-the-hell sigh, "where do we start the search for the King of Hell?"


End file.
